Brown spots spreading fast, help!

[nopami]

Hey guys, could you please help. Autoflower, end of 7th week since sprouted, 3rd week of flowering. I switched to blooming nutes once it stopped stretching, about a week ago. I'm in Biobizz allmix soil (rich soil, pre-fertilised) in a 15L plastic pot and using the organic Biobizz nutes according to the recommended nutrient schedule.

A week ago I noticed the brown spots and yellowing tips on the lower larger fan leaves. Any idea what it might be? I read it's quite difficult to overfeed with organic nutes like Biobizz, and I'm never above the recommended doses (usually slightly below even) - so I don’t think its over feeding. Didn’t have any issues during veg.

I read it could be calmag - so 5 days ago I started adding some, but it keeps spreading.

In terms of water and pH, I use tap water and used pH strips that show somewhat between 6 and 7, closer to 7 (that's after adding nutes). From the local authority of where I live, the tap water is said to be pH 7.7 and "soft" water.

This is a week ago.

And that is today - it started spreading on smaller and upper fan leaves too.

Apart from that, plant looks healthy overall…

 

[GNick55]

Hey guys, could you please help. Autoflower, end of 7th week since sprouted, 3rd week of flowering. I switched to blooming nutes once it stopped stretching, about a week ago. I'm in Biobizz allmix soil (rich soil, pre-fertilised) in a 15L plastic pot and using the organic Biobizz nutes according to the recommended nutrient schedule.

A week ago I noticed the brown spots and yellowing tips on the lower larger fan leaves. Any idea what it might be? I read it's quite difficult to overfeed with organic nutes like Biobizz, and I'm never above the recommended doses (usually slightly below even) - so I don’t think its over feeding. Didn’t have any issues during veg.

I read it could be calmag - so 5 days ago I started adding some, but it keeps spreading.

In terms of water and pH, I use tap water and used pH strips that show somewhat between 6 and 7, closer to 7 (that's after adding nutes). From the local authority of where I live, the tap water is said to be pH 7.7 and "soft" water.

This is a week ago.
View attachment 2003296

And that is today - it started spreading on smaller and upper fan leaves too.

View attachment 2003299
View attachment 2003300

Apart from that, plant looks healthy overall…

looks like from overwatering and possibly too small a pot, might be heating up too hot in the sun..
post pictures of whole plant and pot..

 

[Captspaulding]

looks like from overwatering and possibly too small a pot, might be heating up too hot in the sun..
post pictures of whole plant and pot..

Maybe ph imbalance you think?

 

[GNick55]

Maybe ph imbalance you think?

could really be a few things going on

 

[nopami]

looks like from overwatering and possibly too small a pot, might be heating up too hot in the sun..
post pictures of whole plant and pot..

Hi, thank you for helping, I’m attaching a few pictures of the whole plant from various angles.

She’s growing outdoors, usually keep her on the grass except in rainy weather where she’s on the terrace under roof. Day time temperatures have been between 75 and 90F (23-33 celsius). I really doubt it’s over watering - I’m only watering when the pot gets very light and dries out, these days that’s usually every couple of days.

Past week has been a little windy, not sure if that can have any such effect on the leaves, I’d be surprised.

 

[GNick55]

Hi, thank you for helping, I’m attaching a few pictures of the whole plant from various angles.

She’s growing outdoors, usually keep her on the grass except in rainy weather where she’s on the terrace under roof. Day time temperatures have been between 75 and 90F (23-33 celsius). I really doubt it’s over watering - I’m only watering when the pot gets very light and dries out, these days that’s usually every couple of days.

Past week has been a little windy, not sure if that can have any such effect on the leaves, I’d be surprised.

View attachment 2003537View attachment 2003538
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View attachment 2003541

ok i’ll look later if you don’t get help .. mom working watering golf greens

 

[nopami]

Maybe ph imbalance you think?

I tested again today. Water with nutes is at 7. Also tested the run off water, it’s somewhere slightly above 6… Don’t have more precise measurements as I’m using pH strips.

 

[Captspaulding]

I tested again today. Water with nutes is at 7. Also tested the run off water, it’s somewhere slightly above 6… Don’t have more precise measurements as I’m using pH strips.

That’s ok then, I’m going to suggest a top coat worm castings or blood meal on your soil a 1/4-1/2 all the way from stalk to pots edge to help with that leaf fade. It’ll green things up as you give flowering nutrients. If you are giving cal mag now after there has been damage, that is going to stay, any fix is not going to happen over night, so keep giving the cal mag, I suspect a lot of the more pronounced damage is from that, but it also seem like your nitrogen is off a tad. This is why I suggest a top coat. Watering will then make that nitrogen rich stuff immediately available after. You can even scratch it down into the crust of your soil. This will take about a week to get right.

 

[TinFoilHat]

Next time, make sure you use a bigger pot. You can take an auto to almost the end with a bigger pot and no added nutes.

 

[nopami]

That’s ok then, I’m going to suggest a top coat worm castings or blood meal on your soil a 1/4-1/2 all the way from stalk to pots edge to help with that leaf fade. It’ll green things up as you give flowering nutrients. If you are giving cal mag now after there has been damage, that is going to stay, any fix is not going to happen over night, so keep giving the cal mag, I suspect a lot of the more pronounced damage is from that, but it also seem like your nitrogen is off a tad. This is why I suggest a top coat. Watering will then make that nitrogen rich stuff immediately available after. You can even scratch it down into the crust of your soil. This will take about a week to get right.

Thank you for the advice. I’ve never used worm castings before. Just to make sure I get it right - I add a top coat of about 1/2 inch on top of the soil, covering til the pots edge. Not sure what you meant by “scratch down into the crust of the soil”? Thanks!

 

[Captspaulding]

Thank you for the advice. I’ve never used worm castings before. Just to make sure I get it right - I add a top coat of about 1/2 inch on top of the soil, covering til the pots edge. Not sure what you meant by “scratch down into the crust of the soil”? Thanks!

Take a fork, and break up the top of the dirt in your pot, add the castings all the way to the edge of the pot, then take that fork and work the castings down into the medium. Scratch it in!

 

[Harpua88]

Take a fork, and break up the top of the dirt in your pot, add the castings all the way to the edge of the pot, then take that fork and work the castings down into the medium. Scratch it in!

This is great advice. Soil can cake up as it dries out, over time and many waterings the soil can take on the shape of the pot......it also shrinks back/in from the sides, creating a space all around between the soil and the pot. You water, and since the top of the soil is dry, crusty, just like a bone dry sponge doesn't easily absorb water........the water doesn't immediately penetrate, rolls off to the sides, and right down that gap. Instead of absorbing and gently soaking down, the water rolls righ over the soil, right fown the sides and you've just watered the bottom of the pot, and right out of the holes. It's almost like a cruel joke. The drier your soil, the more you want it to soak up your watering. But the drier your soil, the less it can nicely absorb, the more it runs dow and out.

The answer isn't to water more often so it doesn't happen.......because we want the soil to dry out between waterings. Don't fight that. Instead. "Prep your soil gor watering". A fork, your hands are probably even better because you can feel the dryness, how it's dry, how it's made a crust........you don't just want to scratch the top of your soil, you want to reshape it a bit, pull some in towards the stem, push some down around the sides, filling that gap that time and drying has made. You're also breaking up that crustiness that acts like a barrier to absorbtion. In the anology of a dried sponge that doesn't absorb water, if you just slight moisten the sponge as you squeeze it abd work it a little, now it will absorb water........you've prepped it.

 

[sins]

Calcium/magnesium deficiency or leaf rust. Rub with your finger if ya get spores on ya finger its leaf rust if not deficiency. Next time put some egg shells in when ya mix ya soil.

 

[GNick55]

Calcium/magnesium deficiency or leaf rust. Rub with your finger if ya get spores on ya finger its leaf rust if not deficiency. Next time put some egg shells in when ya mix ya soil.

no if anything it’s leaf septoria..
probably brought on by overwatering and being rootbound..

 

[sins]

Think that's leaf rust here in UK, or last term I dunno either way fungus spores will be release when rubbed.

 

[Captspaulding]

That’s a 5 gallon or larger pot. That plant isn’t huge or anything, it may be root bound sure, but I’ve seen and grown personally waaaaaaay larger plants than that in a five and they were nowhere near rootbound, op was saying he practices pretty sound watering, so unless that plant has been swimming in crazy high humidity for weeks at a time, then I could see septoria, but that stuff is more rare. That’s just my 2 cents. Have a good one homies! Hope you get it sorted sooner than later.

 

[GNick55]

That’s a 5 gallon or larger pot. That plant isn’t huge or anything, it may be root bound sure, but I’ve seen and grown personally waaaaaaay larger plants than that in a five and they were nowhere near rootbound, op was saying he practices pretty sound watering, so unless that plant has been swimming in crazy high humidity for weeks at a time, then I could see septoria, but that stuff is more rare. That’s just my 2 cents. Have a good one homies! Hope you get it sorted sooner than later.

no way that’s a 5 gallon pail??
5 litres maybe?

 

[Captspaulding]

no way that’s a 5 gallon pail??
5 litres maybe?

I’m pretty sure it’s close. I’m not trying to step on toes here, but it looks to me to be sitting on 18in tile, if that’s the case, that is a giant 5 liter pot.

 

[nopami]

Take a fork, and break up the top of the dirt in your pot, add the castings all the way to the edge of the pot, then take that fork and work the castings down into the medium. Scratch it in!

Thanks that’s really helpful, will do that. I have 5 other plants that are 2 weeks younger, in the same soil with same nutes. They are in preflowering, haven’t started showing obvious deficiencies, but some bottom large fan leaves are getting slightly paler. Would you recommend I add the castings to those plants too, as a prevention? Or do I risk excess feeding/excess nitrogen?

Calcium/magnesium deficiency or leaf rust. Rub with your finger if ya get spores on ya finger its leaf rust if not deficiency. Next time put some egg shells in when ya mix ya soil.

I saw that it could be leaf rust/fungal, but I rubbed those brown spots and nothing comes off at all, nothing on my fingers. So I assumed it wasn’t spores of fungus.

no if anything it’s leaf septoria..
probably brought on by overwatering and being rootbound..

If so, any ways of confirming the diagnosis? Should it leave spores or smudges on my fingers when I rub it?

That’s a 5 gallon or larger pot. That plant isn’t huge or anything, it may be root bound sure, but I’ve seen and grown personally waaaaaaay larger plants than that in a five and they were nowhere near rootbound, op was saying he practices pretty sound watering, so unless that plant has been swimming in crazy high humidity for weeks at a time, then I could see septoria, but that stuff is more rare. That’s just my 2 cents. Have a good one homies! Hope you get it sorted sooner than later.

Close enough! That is a 15 Litres (4 US gallons) pot. The plant is about 3 feet tall. And yes indeed I do think the same, I am quite careful with my watering, in fact I’m pretty sure I underwatered during veg. Humidity is usually about 40-50% during the day, since I started growing it has been quite hot and dry. Only at night it goes up to 60-70% before dawn. In fact you can see here on this graph from my hygrometer:

 

[Captspaulding]

Thanks that’s really helpful, will do that. I have 5 other plants that are 2 weeks younger, in the same soil with same nutes. They are in preflowering, haven’t started showing obvious deficiencies, but some bottom large fan leaves are getting slightly paler. Would you recommend I add the castings to those plants too, as a prevention? Or do I risk excess feeding/excess nitrogen?


I saw that it could be leaf rust/fungal, but I rubbed those brown spots and nothing comes off at all, nothing on my fingers. So I assumed it wasn’t spores of fungus.


If so, any ways of confirming the diagnosis? Should it leave spores or smudges on my fingers when I rub it?


Close enough! That is a 15 Litres (4 US gallons) pot. The plant is about 3 feet tall. And yes indeed I do think the same, I am quite careful with my watering, in fact I’m pretty sure I underwatered during veg. Humidity is usually about 40-50% during the day, since I started growing it has been quite hot and dry. Only at night it goes up to 60-70% before dawn. In fact you can see here on this graph from my hygrometer:
View attachment 2003789

Your weather is kinda awesome, that high humidity burns off fast I bet with 40-50% days…..you can roll the pot between your hands, break the soils hold from the side of the pot, pop that sucker out and check the root condition, if you can…..